U.S. factory activity contracted in May for a third consecutive month and a gauge of imports fell to a 16-year low as firms pulled back in the face of higher tariffs.

The Institute for Supply Management’s manufacturing index edged down 0.2 point last month to 48.5, according to data released Monday. Readings below 50 indicate contraction.

Two of the report’s trade-related indexes highlighted the widespread uncertainty caused by the uneven rollout and frequent changes in tariffs. The ISM’s import measure dropped 7.2 points, one of the largest monthly slides on record, to 39.9.

That marked a departure from earlier this year when some firms were importing more to get ahead of tariffs. The gauge of exports fell to the lowest level in five years, possibly a reflection of retaliatory tariffs from other nations on US producers.

“We still feel that the economy overall over a longer period of time is still in expansion,” Susan Spence, chair of the ISM Manufacturing Business Survey Committee, said on a call with reporters. “We are really hopeful that the tariff uncertainties can come to a conclusion, and that the purchasing managers that are working so hard to deal with this whiplash can focus on the normalness of what their job should be.”

Seven industries reported contraction in May, led by paper products, wood and printing. Seven industries, including plastics and rubber, nonmetallic minerals and petroleum, expanded.

The ISM factory inventories index showed the largest contraction in four months.

“Increases in factory activity were offset by shrinking inventories of raw materials. That may correspond to a pull-forward of activity while tariffs were paused, but customer inventories are also low, setting the stage for a future increase in orders,” said Stuart Paul, economist at Bloomberg Economics.

The confusion over evolving trade policy is also making it difficult on supply managers to efficiently source goods and materials. The ISM’s supplier deliveries index climbed to the highest level since June 2022, indicating extended delivery times.

The report also showed the fallout on demand from higher duties. Bookings contracted for a fourth month, and order backlogs shrank at the slowest pace since September 2022.